This paper reports on the catalyst stability of the hydrotreatment of HTL (Hydrothermal Liquefaction) biocrudes to produce finished liquid transportation fuel blendstocks. We report the stable hydrotreating of HTL biocrude derived from sewage sludge and food waste over industrially relevant hydrotreating CoMo and NiMo catalysts at relevant catalyst activities. The use of wet-wastederived HTL biocrudes derived from both food waste and sewage sludge in the hydrotreater campaign strengthens the case that HTL biocrudes derived from a variety of wet-waste feedstocks can be upgraded without significant catalyst instability over industrially relevant hydrotreater time-periods. Stable hydrotreating performance was obtained with each feedstock. The overall yield was approximately 85% with all HTL biocrudes. Over 1500 h of steady-state operation, minimal deactivation was observed. These results indicate that a hydrotreatment process to upgrade can be stable for industrially relevant times, a critical roadblock to derisking commercialization. The upgraded product produces a diesel-rich (∼70% in the 150−350 °C range) fuel blendstock, with high cetane due to the high fraction of alkanes. Further, we report the impact of process levers on hydrotreating performance on a fully broken-in catalyst (following 1500 h of steady-state operation). The long-term catalyst stability presented here is an important demonstration to derisk HTL commercialization.

Hydrothermal liquefaction (HTL) uses heat and pressure to liquefy the organic matter in biomass/waste feedstocks to produce biocrude. When hydrotreated the biocrude is converted into transportation fuels including sustainable aviation fuel (SAF). Further, by liquifying the organic matter in wet wastes such as sewage sludge, manure, and food waste, HTL can prevent landfilling or other disposal methods such as anerobic digestion, or incineration. A significant roadblock to the development of a new route for SAF is the strict approval process, and the large volumes required (>400 L) for testing. Tier α and β testing can predict some of the properties required for ASTM testing with <400 mL samples. The current study is the first to investigate the potential for utilizing wet-waste HTL biocrude (WWHTLB) as an SAF feedstock. Herein, several WWHTLB samples were produced from food waste, sewage sludge, and fats, oils, and grease, and subsequently hydrotreated and distilled to produce SAF samples. The fuels (both undistilled and distilled samples) were analyzed via elemental and 2D-GC-MS. Herein, we report the Tier α and β analysis of an SAF sample derived originally from a WWHTLB. The results of this work indicate that the upgraded WWHTLB material exhibits key fuel properties, including carbon number distribution, distillation profile, surface tension, density, viscosity, heat of combustion, and flash point, which all fall within the required range for aviation fuel. WWHTLB has therefore been shown to be a promising candidate feedstock for the production of SAF.

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This paper proposes a new static reconfiguration technique to configure the modules in the Photo-Voltaic (PV) array so as to enhance the generated power from the array under partial shading conditions. In this approach, the physical location of the modules in a Total Cross Tied (TCT) connected PV array is arranged based on the Magic Square (MS) pattern so as to distribute the shading effect over the entire array. Further, this arrangement of modules is done without altering the electrical connection of the modules in the array. The MS arrangement reduces the effect of shading of modules in any row thereby enhancing the generated PV power. The MS pattern based PV array configuration has only one Global Maximum Power Point at the right most peak in the PV curve as compared to the conventional TCT configuration under partially shaded conditions. Thus, the proposed MS scheme evidently avoids the need for complex Maximum-Power-Point-Tracking algorithms. The performance of the system is investigated for different shading patterns and the results show that positioning the modules of the array according to MS pattern provides improved performance under partially shaded conditions.

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